1196 PHYSIOLOGY 



taking up particles of foreign matter and effete red corpuscles. The process 

 of phagocytosis, which was described under the cellular mechanisms of 

 defence (p. 1022), is in the spleen a normal occurrence. 



A function has also been assigned to the spleen in the formation of red 

 blood-corpuscles, but the evidence is not sufficient to determine whether 

 such a process occurs normally. 



Chemical analysis of the spleen reveals the presence of a large number of 

 what are called extractives, such as succinic, formic, butyric, and lactic 

 acids, inosit, leucine, xanthine, hypoxanthine, and uric acid. There is also 

 a protein, combined with iron, as well as several pigments probably 

 derived from the hemoglobin of the red corpuscles destroyed by the 

 cells of the splenic pulp. The fact that, in cases where the spleen is 

 pathologically enlarged as in leucocythaemia, the uric acid in the urine 

 is largely increased points to a connection between the spleen and the 

 formation of uric acid in the body. The numerous extractives which are 

 formed probably owe their origin to the destructive changes effected on 

 the effete constituents of the blood by the agency of the splenic pulp-cells. 



